1. Field of the Invention
This specification relates to an apparatus for integrally fixing (fastening) a power semiconductor to a heat sink when fabricating the power semiconductor, such as an inverter and a charger, as core components of an electric vehicle, integrally with a booth bar or the like, and particularly, to an apparatus for fastening a power semiconductor using an integral springy (elastic) clip, capable of fixing a power semiconductor, such as a diode and a MOSFET, using elasticity of a U-shaped clip by integrally molding the clip onto a housing of a plastic module.
2. Background of the Invention
In general, a power semiconductor module is utilized as a core semiconductor device for power conversion which converts a Direct-Current (DC) or Alternating-Current (AC) voltage or current into an appropriate form and size required by a system. The power semiconductor module is often applied to an industrial application field, such as an inverter, an uninterruptible power supply, a welder, an elevator and the like, and a vehicle field.
To overcome problems of heat sinks which are used by being fixed to the power semiconductor devices, the power semiconductor devices such as transistors and MOSFETs are fixed to the heat sinks by directly forming screw insertion holes at the heat sinks or shielding the semiconductor devices by aluminum bars, which are cut by each length, and fixing the aluminum bars to the heat sinks by screws. However, this causes a problem of forming unnecessary screw insertion holes at the heat sinks.
The related art employs a scheme in which the power semiconductor is assembled onto a Printed Circuit Board (PCB) in a soldering manner, and coupled to a heat sink for cooling in a bolting manner. For ensuring assembly efficiency in the scheme, holes are additionally formed at the PCB when the semiconductor is located outside or inside the PCB.
A fixing structure for a power semiconductor according to the related art will be described with reference to FIG. 1, which shows a configuration that the semiconductor is located outside the PCB.
Each of power semiconductor devices 100 is installed on a semiconductor installation portion 19 of a heat sink 18 in a contact state, and bridges 110 is connected to one side of a PCB 20 in a soldering manner. The PCB 20 is inserted into a PCB fixing recess 24 of the heat sink 10. A clip type fixing device 10, as shown in FIG. 1, is separately coupled to each power semiconductor device 100 in a pressing manner to be appropriate for a specific structure of the heat sink.
Referring to FIG. 2, even when a bridge module is employed to connect the power semiconductor to an electronic circuit via a housing, the power semiconductor 100 located below the housing has to be fixed at the outside by a separate fixing clip 60. Here, screws are inserted into fixing openings 133 formed through a semiconductor fixing piece 130 to fix the power semiconductor, and pressing pieces 65 of the fixing clip 60 which is a steel clip elastically fix the power semiconductor. Also, screws inserted into clip fixing openings 67 may be separately used to fix the fixing clip 60.
Here, for a semiconductor with a small capacity, plastic screws are used. However, this has a disadvantage of being vulnerable to heat-resistance. Also, the fixing clip 60 completely covers the semiconductor, which additionally requires a hole for allowing a tool such as a driver to be inserted. This may result in a limitation of a circuit design.
In the related art as shown in FIGS. 1 and 2, the semiconductor is located outside the PCB to couple screws for fixing the semiconductor. Or, if such structure is impossible, a hole for allowing a tool such as a driver or the like to be inserted is required. This lowers a degree of freedom in view of designing patterns of the PCB due to the position limit. In addition, bolts are required for fixing the clip, thereby increasing the number of components.
Furthermore, as aforementioned, the plastic screws are used for fixing the small semiconductor. Accordingly, such screws may be deformed due to heat generation of the semiconductor and thereby a fixing force may be weakened or lost.